KR100497358B1 - Electrophotographic liquid toner having improved fusing performance - Google Patents

Abstract

The electrophotographic liquid toner of the present invention comprises a carrier liquid; A binder resin comprising a thermoplastic (co) polymer core insoluble in the carrier liquid and a (co) polymer graft stabilizer covalently bonded to the thermoplastic (co) polymer core; coloring agent; And a charge control agent, wherein at least one of the thermoplastic (co) polymer core and the graft stabilizer comprises repeating units derived from polymerizable monomers having one or more reactive groups selected from epoxy groups and secondary amine groups It features. According to the present invention, by using a liquid toner containing a binder resin having a group having excellent reactivity at low temperature such as an epoxy group and a secondary amine group, the reactive groups present in the binder resin react with each other in the process of fixing the image. This improves the binding force between the toner particles, which in turn improves the durability of the paper-like receptor. And when the liquid toner of the present invention is used, the durability of the printed image does not decrease even when it is mounted at a low temperature. In addition, since it is possible to fix at a low temperature, it is possible to significantly reduce the amount of vapor resulting from the carrier liquid at the time of fixation, and thus, there is an advantage of reducing the cost of printing manufacturing because the steam capturing system is unnecessary.

Description

Electrophotographic liquid toner having improved fusing performance

The present invention relates to an electrophotographic liquid toner, and more particularly, to an electrophotographic liquid toner using a binder resin having a reactive group.

According to the electrophotographic image forming method, the organic photoconductor is formed by forming a photosensitive layer on a conductive support, and has a plate, disk, sheet, belt or drum form. Looking at the method of forming an image electrophotographically using such an organic photosensitive member is as follows.

First, the surface of the photoconductor is electrostatically uniformly charged, and then the charged surface is irradiated with a laser beam. In the portion where the laser beam is irradiated, positive and negative charges are generated and move to the surface, and as the electric charges charged on the surface are neutralized, the surface potential is changed to form a latent image.

Thereafter, when a developing process is performed using a toner having a predetermined color, an image is formed on the surface of the organic photoconductor. The image thus formed is transferred to a receptor surface such as paper. This image forming process is repeated a plurality of times.

In the above-mentioned electrophotographic image forming process, it is classified into a dry method and a wet method according to the toner to be used.

In the case of dry electrophotographic, a solid toner is used.

On the other hand, liquid toners are used in the case of a wet electrophotographic method, and the use of the liquid toner is superior to that of the dry method, and at the same time, it is possible to prevent damage caused by harmful toner dust.

The liquid toner is formed by mixing a carrier liquid, a colorant, a binder resin, and a charge control agent. In the case of using such a liquid toner, however, an image is transferred onto a container such as paper, and then vapor is generated by the carrier liquid contained in the liquid toner while passing through a high temperature fixing roller. Since such vapors should not be released outside of a certain concentration, a device for capturing and removing them is essential. And in order to reduce the generation of steam, the temperature of the fixing roller should be lowered.

However, when the temperature of the fixing roller is lowered in this way, an excess of carrier liquid remains in the image, which causes a problem that the durability of the printed image is lowered.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above problems and to provide a liquid toner having improved fixing performance and a method of manufacturing the same.

In the present invention to achieve the first technical problem, a carrier liquid;

A binder resin comprising a thermoplastic (co) polymer core insoluble in the carrier liquid and a (co) polymer graft stabilizer covalently bonded to the thermoplastic (co) polymer core;

coloring agent; And

A charge control agent,

At least one of the thermoplastic (co) polymer cores and graft stabilizers,

It provides an electrophotographic liquid toner comprising repeating units derived from polymerizable monomers having at least one reactive group selected from an epoxy group and a secondary amine group.

The polymerizable monomer having an epoxy group is selected from the group consisting of 1,2-epoxy-9-decene, 1,2-epoxy-7-octene, 1,2-epoxy-5-hexene and glycidyl methacrylate. At least one polymerizable monomer having a secondary amine group is at least one selected from the group consisting of diacetone acrylamide and N-methyl-2-methylallylamine.

 The graft stabilizer includes a repeating unit derived from a (meth) acrylic monomer having 6 to 30 carbon atoms. The said C6-C30 (meth) acrylic-type monomer is hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl methacrylate, decyl (meth) acrylate, and dodecyl acrylate. It is preferably at least one selected from the group consisting of lauryl acrylate, octadecyl acrylate, stearyl acrylate, bihenyl acrylate, trimethyl cyclohexyl methacrylate.

The thermoplastic (co) polymer core includes a repeating unit derived from a (meth) acrylic monomer having 4 to 30 carbon atoms. Wherein the (meth) acrylic monomer having 4 to 30 carbon atoms is methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, trimethyl cyclohexyl methacrylate, octadecyl It is preferably at least one selected from the group consisting of acrylates and bihenyl acrylates.

It is preferable that the mixing weight ratio of the said thermoplastic (co) polymer core and a graft stabilizer is 1: 1-15: 1.

In the liquid toner of the present invention, the content of the binder resin is preferably 1 to 20 parts by weight based on 1 part by weight of the colorant.

Charge control agents of the present invention are fatty acid metal salts, sulfo-succinate metal salts, alkyl-benzenesulfonate metal salts, aromatic carboxylic acid metal salts, sulfonic acid metal salts, polyoxyethylated alkylamines, lecithin, polyvinylpyrrolidone, basic barium At least one selected from the group consisting of petronates and calcium petronates, the content of which is preferably 0.001 to 1 parts by weight based on 1 part by weight of the colorant.

The carrier liquid is a branched paraffin solvent, the content of which is preferably 10 to 100 parts by weight based on 1 part by weight of the colorant.

The colorant is preferably at least one selected from the group consisting of phthalocyanine blue, monoarylide yellow, diarylide yellow, arylamide yellow, azo red, quinacridone magenta and carbon black.

The second technical problem of the present invention is to mix (a) a C6-C30 (meth) acrylic monomer , an epoxy group and / or a secondary amine group-containing polymerizable monomer and a polymerization initiator, which are polymerizable monomers for forming a carrier liquid and a graft stabilizer. Then performing a polymerization reaction using the mixture to obtain a graft stabilizer;

(b) a mixture of the graft stabilizer, the carrier liquid, the (meth) acrylic monomer having 4 to 30 carbon atoms as the polymerizable monomer for the thermoplastic (co) polymer core, the epoxy group and / or the secondary amine group-containing polymerizable monomer and the polymerization initiator Next, performing a polymerization reaction using this mixture to form an organosol; And

(c) a method for producing an electrophotographic liquid toner, wherein the above-mentioned electrophotographic liquid toner is obtained by mixing a colorant, a charge control agent and a carrier liquid with the organosol.

In step (b), an ethylenically unsaturated aliphatic isocyanate may be further added.

The ethylenically unsaturated aliphatic isocyanate is particularly preferably 3-isopropenyl dimethylbenzyl isocyanate or 2-cyanoethyl methacrylate.

The present invention utilizes a liquid toner containing a binder resin having a group having excellent reactivity at low temperature, such as an epoxy group and a secondary amine group, so that the reactive groups present in the binder resin in the process of fixing the developed image It is intended to improve the cohesion force between toner particles by causing it to react. Therefore, even when mounted at a low temperature, the durability of the printed image does not decrease. In addition, since it is possible to fix at a low temperature, the amount of vapor originating from the liquid toner can be significantly reduced, thereby eliminating the need for a vapor capturing system, thereby lowering the printing manufacturing cost.

The liquid toner of the present invention is a graft comprising a carrier liquid and a binder resin, a thermoplastic (co) polymer core insoluble in the carrier liquid, and a (co) polymer graft stabilizer covalently bonded to the thermoplastic (co) polymer core. (Co) polymer, a coloring agent, and a charge control agent. Wherein at least one of the thermoplastic (co) polymer cores and graft stabilizers comprises repeating units derived from polymerizable monomers having at least one reactive group selected from epoxy groups and secondary amine groups.

In the present invention, the content of the binder resin is preferably 1 to 20 parts by weight, preferably 10 to 20 parts by weight, based on 1 part by weight of the colorant. If the content of the binder resin is less than 1 part by weight, the colorant may not be properly fixed to the paper, so that the colorant is buried out of the paper after printing. If the content is more than 20 parts by weight, the printed image is not clear because the amount of the colorant is small. It is unfavorable because it is not cloudy.

The polymerizable monomer having an epoxy group is selected from the group consisting of 1,2-epoxy-9-decene, 1,2-epoxy-7-octene, 1,2-epoxy-5-hexene and glycidyl methacrylate. At least one selected may be used, and at least one selected from the group consisting of diacetone acrylamide and N-methyl-2-methylallylamine may be used as the polymerizable monomer having the secondary amine group.

The charge control agent constituting the liquid toner of the present invention provides uniform charge polarity to the toner particles, which includes fatty acid metal salts, sulfo-succinate metal salts, alkyl-benzenesulfonate metal salts, aromatic carboxylic acid metal salts, sulfonic acid metal salts, At least one selected from the group consisting of polyoxyethylated alkylamines, lecithin, polyvinylpyrrolidone, basic barium petronates and calcium petronates. Herein, the content of the charge control agent is preferably 0.001 to 1 part by weight based on 1 part by weight of the colorant. In this case, when the content of the charge control agent is out of the range, the toner particles may not be properly charged to obtain an image of a desired shape or the optical density of the printed image may be low to obtain a clear image. There is a problem.

 The carrier liquid must be chemically inert with respect to the materials or devices used in liquid electrophotographic processes, in particular the photoreceptors and their release surfaces.

Non-limiting examples of carrier fluids include aliphatic hydrocarbons (n-pentane, hexane, heptane, etc.), alicyclic hydrocarbons (cyclopentane, cyclohexane, etc.), aromatic hydrocarbons (benzene, toluene, xylene, etc.), halogenated hydrocarbon solvents ( Chlorinated alkanes, fluorinated alkanes, chlorofluorocarbons and the like), silicone oils and mixtures thereof. Carrier fluids include, in particular, trade names Isopar G, Isopar H, Isopar K, Isopar L, Isopar M, Isopar V (Exxon Corporation), and Norpar 12 (Exxon Corporation). Preferred is a branched paraffin solvent mixture such as Norpar 15 (Exxon Corporation).

The content of such carrier liquid is preferably 10 to 100 parts by weight based on 1 part by weight of the colorant. If the content of the carrier liquid is less than 10 parts by weight, the viscosity of the liquid toner is too high, resulting in a problem of a thin printer in an undesired image area, difficult to control the liquid toner properly, and if it exceeds 100 parts by weight, the colorant concentration of the liquid toner is high. It is undesirable because the optical density of the printed image is too low, or the liquid toner is easily consumed and needs to be replaced frequently.

As the colorant, any colorant known in the art is useful, and includes a material such as a dye and a pigment.

The colorants used in the liquid toner of the present invention are nominally insoluble and not reactive to the carrier liquid, and are useful and effective for visualizing the electrostatic latent image. Non-limiting examples of such colorants include phthalocyanine blue (CI Pigment Blue 15: 1, 15: 2, 15: 3 and 15: 4), monoarylide yellow (CI Pigment Yellow 1, 3, 65) 73 and 74), diarylide yellow (CI Pigment Yellow 12, 13, 14, 17 and 83), arylamide (Hansa) yellow (CI Pigment Yellow 10, 97, 138 and 111), azo red (CI Pigment Red) 3, 17, 22, 23, 38, 48: 1, 48: 2, 52: 1, 81 81.4 and 179), quinacridone magenta (CI Pigment Red 122, 202 and 209), micronized carbon Black pigments such as (Cabot Monarch 120, Cabot Regal 300R, Cabot Regal 350R, Vulcan X72).

Hereinafter, with reference to the accompanying drawings will be described the principle of the present invention.

1 is a schematic diagram showing a state before the liquid toner of the present invention passes through the fixing roller.

Referring to this, the liquid toner has a state in which a binder resin 11 having a reactive group (A) and (B) such as an epoxy group, a secondary amine group, simply surrounds the pigment 10. At this time, the charge control agent 12 is added between the pigment 10 and the binder resin 11 for the purpose of adjusting the polarity and size of the charge on the toner particles.

When the image developed by contacting the liquid toner of FIG. 1 and the photosensitive member is passed through the fixing roller, the chemical reaction of Scheme 1 below is performed between the reactive groups (A) and (B) of the binder resin 21 as shown in FIG. 2A. (Reaction between the epoxy group and the secondary amine) occurs to form a strong covalent bond between the toner particles or the chemical reaction of reaction formula 2 (the epoxy group and the hydroxy period of the cellulose constituting the paper (HO-Cell). ), A covalent bond is formed between the toner particles and the paper, thereby increasing the bonding force between them. In FIG. 2A, reference numeral 20 denotes a pigment and reference numeral 22 denotes a charge control agent. In FIG. 2B, a charge control agent, a pigment, and the like are not shown, and only a binder resin is shown.

Hereinafter, the manufacturing method of the liquid toner according to the present invention will be described.

In preparing the liquid toner of the present invention, it is preferable to add the binder resin in the form of an organosol containing it (dispersibility of the binder resin).

The organosol consists of a core region and a shell region. Such organosol can be prepared by first synthesizing a graft stabilizer forming a shell portion, then adding a polymerizable monomer for forming a core portion with the graft stabilizer, and then polymerizing it. The graft stabilizer here acts to stabilize the toner particles by causing a graft reaction with the resin core portion.

Looking at the manufacturing method of the organosol in more detail as follows.

That is, a carrier liquid, a (meth) acrylic monomer having 6 to 30 carbon atoms, which is a polymerizable monomer for forming a graft stabilizer , an epoxy group and / or a secondary amine group-containing polymerizable monomer and a polymerization initiator are mixed and then polymerized using this mixture. The reaction is carried out to prepare a graft stabilizer.

The temperature of the polymerization reaction varies depending on the type of the polymerizable monomer, but is carried out in the range of 50 to 100 ° C, preferably 70 to 80 ° C.

Examples of the (meth) acrylic monomer having 6 to 30 carbon atoms include hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl methacrylate, decyl (meth) acrylate, and dodecyl acrylate. , Lauryl acrylate, octadecyl acrylate, stearyl acrylate, bihenyl acrylate, trimethyl cyclohexyl methacrylate is used.

As the epoxy group-containing polymerizable monomer, 1,2-epoxy-9-decene, 1,2-epoxy-7-octene, 1,2-epoxy-5-hexene and glycidyl methacrylate are used. As the polymerizable monomer having a secondary amine group, at least one selected from the group consisting of diacetone acrylamide and N-methyl-2-methylallylamine is used. Herein, the content of the epoxy group and / or the secondary amine group-containing polymerizable monomer is preferably 3 to 15 parts by weight based on 100 parts by weight of the (meth) acrylic monomer having 6 to 30 carbon atoms.

The polymerization initiator for initiating the polymerization reaction is not particularly limited,

Non-nitrile-based or nitrile-based azo compounds may be used, and specific examples thereof include dimethyl 2,2'-azobis (2-methylpropionate). It is preferable that it is 0.5-2.5 weight part based on 100 weight part of 30 (meth) acrylic-type monomers.

The carrier liquid is particularly preferably a branched paraffin solvent, the content thereof is preferably 100 to 1000 parts by weight based on 100 parts by weight of the (meth) acrylic monomer having 6 to 30 carbon atoms.

Subsequently, polymerization containing a (meth) acrylic monomer having 4 to 30 carbon atoms and an epoxy group and / or a secondary amine group, which is a polymerizable monomer for forming a graft stabilizer, a carrier liquid, and a thermoplastic (co) polymer core obtained according to the above procedure. The monomer and the polymerization initiator are mixed and the mixture is subjected to a polymerization reaction to form an organosol. The mixture may further add an ethylenically unsaturated aliphatic isocyanate, which is a polymerizable monomer for forming a thermoplastic (co) polymer core, and the reason for adding the same will be described later. The content of such ethylenically unsaturated aliphatic isocyanate is 1 to 10 parts by weight based on 100 parts by weight of (meth) acrylic monomer having 4 to 30 carbon atoms. Specific examples thereof include 3-isopropenyl dimethylbenzyl isocyanate or 2-cyanoethyl methacrylate.

Specific examples of the (meth) acrylic monomer having 4 to 30 carbon atoms include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, trimethyl cyclohexyl methacrylate, Bihenyl acrylate, octadecyl acrylate and the like, and trimethyl cyclohexyl methacrylate, methyl methacrylate or ethyl acrylate are most preferred.

The content of the epoxy group and / or the secondary amine group-containing polymerizable monomer is preferably 3 to 15 parts by weight based on 100 parts by weight of the (meth) acrylic monomer having 4 to 30 carbon atoms, and the content of the polymerization initiator is 4 to 30 carbon atoms. It is preferably 0.5 to 2.5 parts by weight based on 100 parts by weight of the (meth) acrylic monomer.

The temperature of the polymerization reaction varies depending on the type of polymerizable monomer, but is carried out in the range of 50 to 100 ° C, preferably 70 to 80 ° C.

The graft stabilizer obtained according to the above process is chemically bonded to the thermoplastic (co) polymer core (ie, grafted to the core) or adsorbed on the core surface to remain in the physically bound essential region of the core. Many reactions known to those skilled in the art are effective for grafting graft stabilizers to cores during free radical polymerization.

Common grafting methods include random grafting of multifunctional free radicals; Ring-opening polymerization of cyclic ethers, esters, amides or acetals; Epoxidation; Reaction of hydroxy or amino chain transfer agents with unsaturated end groups; Esterification reactions (ie, glycidyl methacrylate reacts with methacrylic acid to proceed with ester reactions under tertiary amine catalysts) and condensation or polymerization reactions.

The graft stabilizer of the present invention preferably has a weight average molecular weight of 50,000 to 1,000,000 Daltons (Da), more preferably 100,000 to 500,000 Da, most preferably 100,000 to 300,000 Da. When the weight average molecular weight of the graft stabilizer is out of the above range, the graft stabilizer is partially out of the partially soluble region and thus does not function as a stabilizer, thereby preventing the formation of ink particles, thereby dispersing and stability of the ink particles. This is not preferable because it becomes poor.

In the present invention, the graft stabilizer is covalently bonded to a thermoplastic (co) polymer core that is insoluble in the carrier liquid using a grafting site. The grafting site introduces a hydroxyl group to the graft stabilizer during the free radical polymerization, and in the subsequent subsequent non-free radical step, all or part of these hydroxyl groups are ethylene unsaturated aliphatic isocyanates (e.g. 3- Isopropenyl dimethylbenzyl isocyanate or 2-cyanatoethylmethacrylate) and a catalyst such as dibutyltin dilaurate to form a polyurethane bond. The graft stabilizer is then covalently bound to the initial insoluble acrylic acid (co) polymer core through a reaction between the unsaturated vinyl group of the grafting site and the ethylenically unsaturated core monomer during the subsequent free radical polymerization step.

In the organosol of the present invention, the mixed weight ratio of the thermoplastic (co) polymer core and the graft stabilizer is 1: 1 to 15: 1, more preferably 2: 1 to 10: 1, and 4: 1 to 8: 1. Particularly preferred. If the mixed weight ratio between the thermoplastic (co) polymer core and the graft stabilizer is out of the above range, an undesirable effect is obtained. For example, if the core / shell ratio exceeds 15, the graft stabilizer for stabilizing three-dimensionally without organosol is not aggregated, and if the core / shell ratio is less than 1, the driving force of the polymerization reaction is insufficient so that the shell A copolymer solution in which a separate particulate phase is formed that is not a stable organosol dispersion is formed.

As mentioned above, after forming an organosol using the polymerizable monomer containing an epoxy containing monomer and / or a secondary amine containing monomer used as binder resin, a charge control agent, a coloring agent, and a carrier liquid are added to this organosol. And mixing to complete the liquid toner.

Hereinafter, the present invention will be described with reference to the following examples, but the present invention is not limited only to the following examples.

Preparation Example 1

2560 g of Norpar 12 (Exxon), 796 g of lauryl methacrylate, 80 g of 1,2-epoxy-9-decene, 27 g of 2-hydroxyethyl methacrylate and dimethyl 2,2'-azobis (2 as a polymerization initiator 8 g of -methyl propionate) (Dimethyl 2,2'-azobis (2-methylpropionate)} (trade name-V601, Wako chem., Japan) was mixed and stirred at 250 rpm under a nitrogen gas atmosphere at 70 캜. . The reaction mixture was then reacted for 16 hours with stirring at 90 ° C. at 250 rpm.

14 g of dibutyltin dilaurate and 41 g of 3-isopropenyl dimethylbenzyl isocyanate were added to the reaction mixture, which was then reacted at 70 ° C. under a nitrogen gas atmosphere at 250 rpm for 6 hours to prepare a graft stabilizer. .

240 g of the graft stabilizer, 2750 g of norpar 15, 350 g of ethyl methacrylate, 100 g of bihenyl acrylate, 45 g of 1,2-epoxy-9-decene and dimethyl 2,2'-azobis (2-methylpropio as a polymerization initiator Nate) {Dimethyl 2,2'-azobis (2-methylpropionate)} (trade name-V601, Wako chem. Japan) was mixed with 8 g, and then it was stirred for 16 hours while stirring at a speed of 250 rpm under 75 ° C. and nitrogen gas atmosphere. Reaction to complete the organosol.

Preparation Example 2

Norpar 15 2560g, lauryl methacrylate 796g, diacetone acrylamide 80g, 2-hydroxyethyl methacrylate 27g and dimethyl 2,2'-azobis (2-methylpropionate) {Dimethyl 2 as polymerization initiator , 2'-azobis (2-methylpropionate)} (trade name-V601, Wako chem. Japan) was mixed and reacted for 16 hours with stirring at a speed of 250 rpm under 70 ° C. and nitrogen gas atmosphere. Subsequently, the reaction mixture was heated to 90 ° C. and maintained for about 1 hour, and then cooled to 70 ° C. again.

14 g of dibutyltin dilaurate and 41 g of 3-isopropenyl demethylbenzyl isocyanate were added to the reaction mixture, followed by reaction at 70 ° C. under a nitrogen gas atmosphere with stirring at 250 rpm for 6 hours to obtain a graft stabilizer.

240 g of the graft stabilizer, 2750 g of norpar 15, 350 g of ethyl methacrylate, 100 g of bihenyl acrylate, 45 g of diacetone acrylamide and dimethyl 2,2'-azobis (2-methylpropionate) {Dimethyl 2 as a polymerization initiator , 2'-azobis (2-methylpropionate)} (trade name-V601, Wako chem. Japan) was added thereto, and the mixture was reacted for 16 hours while stirring at a speed of 250 rpm in a nitrogen gas atmosphere at 75 ° C. to prepare an organosol.

Preparation Example 3

Norpar 15 2560 g, lauryl methacrylate 796 g, 1,2-epoxy-9-decene 80 g, 2-hydroxyethyl methacrylate 27 g and dimethyl 2,2'-azobis (2-methylpropio as a polymerization initiator Nate) {Dimethyl 2,2'-azobis (2-methylpropionate)} (trade name-V601, Wako chem. Japan) was added thereto and reacted for 16 hours with stirring at a speed of 250 rpm under 70 ° C. and nitrogen gas atmosphere. . Subsequently, the reaction mixture was heated to 90 ° C. and maintained for about 1 hour, and then cooled to 70 ° C. again.

41 g of 3-isopropenyl dimethylbenzyl dimethylbenzyl isocyanate was added to the reaction mixture, which was then reacted for 6 hours while stirring at 250 rpm under a nitrogen gas atmosphere at 70 ° C. to prepare a graft stabilizer.

240 g of the graft stabilizer, 2750 g of norpar 15, 350 g of ethyl methacrylate, 100 g of bihenyl acrylate, 45 g of diacetone acrylamide and 8 g of a polymerization initiator were added and stirred at a speed of 250 rpm in a nitrogen gas atmosphere at 75 ° C. for 16 hours. The reaction was carried out to prepare an organosol.

Example 1

100 g of organosol (solid content (binder resin): 18%) prepared according to Preparation Example 1 in a milling cylinder 100g, 18 g of organosol (solid content (binder resin) content according to Preparation Example 2): 18% ) 100 g, 4 g of phthalocyanine blue pigment, 0.8 g of Zr-HEXCEM were added, and about 400 g of glass beads of 1 mm diameter were added thereto. The mixture was then milled at 35 ° C. at 35 ° C. for about 3 hours to complete the liquid toner.

Example 2

To the milling cylinder was added 100 g of Norpar 15, 200 g of organosol (solid content (binder resin content: 18%) prepared according to Preparation Example 1), 4 g of phthalocyanine blue pigment, 0.8 g of Zr-HEXCEM, and 1 mm in diameter thereto. About 400 g of glass beads were added. The mixture was then milled at 35 ° C. at 35 ° C. for about 3 hours to complete the liquid toner.

Example 3.

To the milling cylinder was added 100 g of norpar 15 , 200 g of organosol (solid content (binder resin content: 18% ) prepared according to Preparation Example 3 above), 4 g of phthalocyanine blue pigment, 0.8 g of Zr-HEXCEM, 400 g of 1 mm diameter glass beads were added. This mixture was then milled at 35 ° C. for about 3 hours at 4000 rpm to complete the liquid toner.

Comparative Production Example 1

2560 g of norpar 15, 796 g of lauryl methacrylate, 27 g of 2-hydroxyethyl methacrylate and dimethyl 2,2'-azobis (2-methylpropionate) {Dimethyl 2,2'-azobis () as a polymerization initiator. 2-methylpropionate)} (trade name-V601, Japan Wako chem.) Was mixed, and the reaction was carried out while stirring this at a rate of 250 rpm under a nitrogen gas atmosphere of 70 ℃. The reaction mixture was then reacted for 16 hours with stirring at 90 ° C. at 250 rpm.

14 g of dibutyltin dilaurate and 41 g of 3-isopropenyl dimethylbenzyl isocyanate were added to the reaction mixture, which was then reacted at 70 ° C. under a nitrogen gas atmosphere at 250 rpm for 6 hours to prepare a graft stabilizer. .

240 g of the graft stabilizer, 2750 g of norpar 15, 350 g of ethyl methacrylate, 100 g of bihenyl acrylate, 45 g of 1,2-epoxy-9-decene and dimethyl 2,2'-azobis (2-methylpropio as a polymerization initiator Nate) {Dimethyl 2,2'-azobis (2-methylpropionate)} (trade name-V601, Wako chem. Japan) was mixed with 8 g, and then it was stirred for 16 hours while stirring at a speed of 250 rpm under 75 ° C. and nitrogen gas atmosphere. Reaction to complete the organosol.

Comparative Example 1

To the milling cylinder was added 100 g of norpar 15, 100 g of organosol (solid content (binder resin content: 18%) prepared according to Comparative Production Example 1), 4 g of phthalocyanine blue pigment, and 0.8 g of Zr-HEXCEM. Then, about 400g of 1mm diameter glass beads were added thereto. The mixture was then milled at 35 ° C. for about 3 hours at a rate of 4000 RPM to complete the liquid toner.

In the liquid toner prepared according to Example 1 and Comparative Example 1, the viscosity change with temperature was investigated, and the result is shown in FIG. 3.

Referring to FIG. 3, the liquid toner of Example 1 increased in viscosity at around 100 ° C. as compared to the liquid toner of Comparative Example 1. FIG. This is because the liquid toner of Example 1 reacts with the reactive group epoxy group and the secondary amine group of the binder resin to form a three-dimensional network structure.

In addition, the durability of the image formed according to the electrophotographic method according to the number of passes of the printing paper passed through the fixing roller adjusted to 150 ℃ using the liquid toner prepared according to Example 1 and Comparative Example 1, The result is shown in FIG. 4. Durability here was assessed by placing a white cloth on the image, placing a weight of 500g, rubbing a portion of the image five times, and then displaying the percentage of the optical density of the rubbed / unrubbed portion of the image.

Referring to FIG. 4, it can be seen that the liquid toner of Example 1 has an increased binding force between toner particles, so that the durability of an image formed using the toner is superior to that of Comparative Example 1 .

According to the present invention, by using a liquid toner containing a binder resin having a group having excellent reactivity at low temperature such as an epoxy group and a secondary amine group, the reactive groups present in the binder resin react with each other in the process of fixing the image. This improves the binding force between the toner particles, which in turn improves the durability of the paper-like receptor. And with the liquid toner of the present invention, even if it is fixed at a low temperature, the durability of the printed image does not decrease. In addition, since it is possible to fix at a low temperature, it is possible to significantly reduce the amount of vapor resulting from the carrier liquid at the time of fixation, and thus, there is an advantage of reducing the cost of printing manufacturing because the steam capturing system is unnecessary.

1 is a schematic diagram of a state before the liquid toner of the present invention passes through the fixing roller,

2A-B are diagrams showing the state after the reaction between the reactive groups of the binder resin occurs while the liquid toner of the present invention passes through the fixing roller,

3 is a graph showing the viscosity change with temperature in the liquid toner prepared according to Example 1 and Comparative Example 1 of the present invention,

4 is a graph showing a change in durability of an image according to the passing number of fixing rollers when a fixing roller passes a paper having an image formed using the liquid toners prepared according to Example 1 and Comparative Example 1 of the present invention.

<Brief description of the major symbols in the drawings>

10, 20 ... Pigment

11, 21 ... Binder Resin

12, 22. Charge control agent

13, 23. Paper

Claims (15)

Carrier liquids; A binder resin comprising a thermoplastic (co) polymer core insoluble in the carrier liquid and a (co) polymer graft stabilizer covalently bonded to the thermoplastic (co) polymer core; coloring agent; And A charge control agent, At least one of the thermoplastic (co) polymer cores and graft stabilizers, A repeating unit derived from polymerizable monomers having one or more reactive groups selected from epoxy groups and secondary amine groups, The polymerizable monomer having an epoxy group is at least one selected from the group consisting of 1,2-epoxy-9-decene, 1,2-epoxy-7-octene and 1,2-epoxy-5-hexene, The polymerizable monomer having the secondary amine group is at least one selected from the group consisting of diacetone acrylamide and N-methyl-2-methylallylamine. delete delete The graft stabilizer of claim 1, wherein An electrophotographic liquid toner comprising repeating units derived from a (meth) acrylic monomer having 6 to 30 carbon atoms. The (meth) acrylic monomer according to claim 4, wherein the (meth) acrylic monomer having 6 to 30 carbon atoms, Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl methacrylate, decyl (meth) acrylate, dodecyl acrylate, lauryl acrylate, octadecyl acrylate, stearyl Acrylates, bihenyl acrylates, And at least one selected from the group consisting of bihenyl acrylate and trimethyl cyclohexyl methacrylate. The method of claim 1, wherein the thermoplastic (co) polymer core, An electrophotographic liquid toner comprising repeating units derived from a (meth) acrylic monomer having 4 to 30 carbon atoms. The method according to claim 6, wherein the (meth) acrylic monomer having 4 to 30 carbon atoms, At least one selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, trimethyl cyclohexyl methacrylate, bihenyl acrylate, and octadecyl acrylate An electrophotographic liquid toner, characterized in that. The electrophotographic liquid toner according to claim 1, wherein the mixed weight ratio of the thermoplastic (co) polymer core and the graft stabilizer is 1: 1 to 15: 1. The liquid toner of claim 1, wherein the binder resin is present in an amount of 1 to 20 parts by weight based on 1 part by weight of the colorant. The method of claim 1, wherein the charge control agent is a fatty acid metal salt, a sulfo-succinate metal salt, an alkyl-benzene sulfonic acid metal salt, an aromatic carboxylic acid metal salt, a sulfonic acid metal salt, a polyoxyethylated alkylamine, lecithin, polyvinylpyrroli At least one selected from the group consisting of don, basic barium petroleum and calcium petronate, the content of which is 0.001 to 1 part by weight based on 1 part by weight of the colorant. The electrophotographic liquid toner according to claim 1, wherein the carrier liquid is a branched paraffinic solvent, and the content thereof is 10 to 100 parts by weight based on 1 part by weight of the colorant. The method of claim 1, wherein the colorant is at least one selected from the group consisting of phthalocyanine blue, monoarylide yellow, diarylide yellow, arylamide yellow, azo red, quinacridone magenta, and carbon black. Liquid toner. (a) Carrier liquid, a (meth) acrylic monomer having 6 to 30 carbon atoms, which is a polymerizable monomer for forming a graft stabilizer, an epoxy group and / or a secondary amine group-containing polymerizable monomer and a polymerization initiator are mixed, and then the mixture is Performing a polymerization reaction to obtain a graft stabilizer; (b) a mixture of the graft stabilizer, the carrier liquid, the (meth) acrylic monomer having 4 to 30 carbon atoms as the polymerizable monomer for the thermoplastic (co) polymer core, the epoxy group and / or the secondary amine group-containing polymerizable monomer and the polymerization initiator Next, performing a polymerization reaction using this mixture to form an organosol; And (c) A process for producing an electrophotographic liquid toner, wherein a colorant, a charge control agent and a carrier liquid are mixed with the organosol to obtain the electrophotographic liquid toner according to any one of claims 1 to 4. . The method for producing an electrophotographic liquid toner according to claim 13, wherein in step (b), ethylenically unsaturated aliphatic isocyanate is further added. 15. The method of claim 14, wherein the ethylenically unsaturated aliphatic isocyanate is 3-isopropenyl dimethylbenzyl isocyanate or 2-cyanoethyl methacrylate.